feat: add Tabler icons to verify icon library wiring

Adds @tabler/icons-react as a direct dep in admin and checkin
(it was already pulled in transitively via @tecnova/ui) and
uses one icon in each app's primary button — Google brand mark
on the admin login button and an arrow on the checkin submit
button — to confirm the preset's tabler iconLibrary setting and
the data-icon=inline-* hooks render correctly.

Author: ut42tech

apps/admin/package.json

@@ -9,6 +9,7 @@
     "type-check": "tsc --noEmit"
   },
   "dependencies": {
+    "@tabler/icons-react": "^3.42.0",
     "@tecnova/shared": "workspace:*",
     "@tecnova/ui": "workspace:*",
     "better-auth": "^1.6.9",

apps/admin/src/app/login/page.tsx

@@ -1,5 +1,6 @@
 'use client';
 
+import { IconBrandGoogleFilled } from '@tabler/icons-react';
 import { Button } from '@tecnova/ui/components/button';
 import { useState } from 'react';
 import { authClient } from '@/lib/auth-client';
@@ -35,6 +36,7 @@ export default function LoginPage() {
       <h1 className="text-2xl font-bold">テクノバ管理画面</h1>
       <p className="text-zinc-600">許可リストに登録されたメンターのみログインできます</p>
       <Button type="button" size="lg" onClick={signIn} disabled={busy}>
+        <IconBrandGoogleFilled data-icon="inline-start" />
         {busy ? 'リダイレクト中...' : 'Google でログイン'}
       </Button>
       {error && <p className="text-red-600">エラー: {error}</p>}

apps/checkin/package.json

@@ -9,6 +9,7 @@
     "type-check": "tsc --noEmit"
   },
   "dependencies": {
+    "@tabler/icons-react": "^3.42.0",
     "@tecnova/shared": "workspace:*",
     "@tecnova/ui": "workspace:*",
     "@zxing/browser": "^0.2.0",

apps/checkin/src/app/page.tsx

@@ -1,5 +1,6 @@
 'use client';
 
+import { IconArrowRight } from '@tabler/icons-react';
 import type { ScanResponse } from '@tecnova/shared/schemas';
 import { Button } from '@tecnova/ui/components/button';
 import { BrowserMultiFormatReader, type IScannerControls } from '@zxing/browser';
@@ -213,6 +214,7 @@ export default function Home() {
             />
             <Button type="submit" size="lg" disabled={input.length !== 5}>
               チェックイン / アウト
+              <IconArrowRight data-icon="inline-end" />
             </Button>
           </form>
           <button